Fogged, direct positive silver halide emulsion sensitized with an isoindolinone polymethine dye

ABSTRACT

Light-sensitive photographic direct positive material containing at least one fogged silver halide emulsion layer which layer contains a polymethine sensitizer containing an isoindolinone ring.

United States Patent 11 1 Riester et al.

[ FOGGED, DIRECT POSITIVE SILVER IIALIDE EMULSION SENSITIZED WITH AN ISOINDOLINONE POLYMETl-IINE DYE [75] Inventors: Qskar Riester, Leverkusen; Hans Ohlschliiger, Bergisch-Gladbach, Schildgen, both of Germany [73] Assignee: Agla-Gevaert Aktiengesellschaf t,

Leverkusen, Germany 221 Filed: July 12, 1972 211 Appl. N0.;271,1s2

[30] Foreign Application Priority Data July 14. 1971 Germany 2l35l53 [52] US. Cl 96/137, 96/107, 96/108 [51] Int. Cl G03c l/08,-GO3C 1/28 sbo w June 11,1974

Primary Examiner-Ronald H. Smith Assistant ExaminerWon H. Louie, Jr. Attorney, Agent, or Firm-Connolly and Hutz [57] ABSTRACT Y Light-sensitive photographic direct positive material containing at least one fogged silver halide emulsion layer which layer contains a polymethine sensitizer containing an isoindolinone ring.

1 Claim, 5 Drawing Figures FOGGED, DIRECT POSITIVE SILVER IIALIDE EMULSION SENSITIZED WITH AN ISOINDOLINONE POLYMETI-IINE DYE This invention is related to photographic direct positive silver halide emulsions which are spectrally sensitized with polymethine sensitizers which contain an isoindolinone ring.

Numerous sensitizing dyes are known for sensitizing the usual negative silver halide emulsions, e.g., monoor trimethine cyanines, merocyanines or rhodacyanines.

The known sensitizing dyes, however, cannot usually be used for sensitizing direct positive emulsions, i.e., emulsions which are processed to'produce positive images after the usual exposure and development, because they generally cause flattening of the gradation. On the other hand, compounds have already been described which can only be used as sensitizing dyes for direct positive emulsions. ln negative emulsions, these compounds cause fogging and their sensitizing effect is unsatisfactory. Indocyanines, for example, have been used as sensitizing dyes for direct positive emulsions. They are quite suitable sensitizers for the red region of the spectrum but their sensitizing effect is still not quite sufficient. The same applies to the direct positive indole sensitizing dyes for the green region of the spectrum and to the bis-thiazolyl and bis-selenazolyl compounds which are known as direct positive sensitizing dyes.

It is among the objects of the present invention to provide sensitizing dyes for direct positive silver halide emulsions which have a sufficiently intense sensitizing effect and have no disadvantageous effect on the gradation.

We now have found a photographic material containing at least one direct positive silver halide emulsion layer which is spectrally sensitized with polymethine sensitizers containing an isoindolenone ring.

Sensitizers of the following formula are particularly suitable:

atoms which may be substituted, e.g. with phenyl, hydroxyl or halogen such as fluorine, chlorine or bromine, carboxyl, esterified carboxyl, carbamoyl,

sulfo or an esterified sulfo group, (2) cycloalkyl such as cyclohexyl or (3) aryl, in particular phenyl which also may be substituted, e.g. with alkyl or alkoxy having preferably up to three carbon atoms or halogen such as chlorine, bromine or iodine;

n is 0 or 1;

X 9stands for anion, eg. a halide such as chloride,

bromide or iodide, perchlorate, sulfate, methylsulfate, p-toluenesulfonate;

Q represents the ring members required for completing a 5- or 6-membered heterocyclic ring; the heterocyclic group may contain a condensed benzene or naphthalene ring and additional substituents; the heterocyclic groups may be those commonly found in cyanine chemistry, for example those based on thiazole (e.g., thiazole, 4-methylthiazole, 5- methylthiazole, 4,5-dimethylthiazole, 4- phenylthiazole, S-phenylthiazole or 4,5- diphenylthiazole), benzothiazole (e.g., benzothiazole, 4-chlorobenzothiazole, S-chlorobenzothiazole, 6-chlorobenzothiazole, 7-chlorobenzothiazole, 6- bromobenzothiazole, S-iodobenzothiazole, 6-

iodobenzothiazole, 4-methylbenzothiazole, 5-

methylbenzothiazole, o-methylbenzothiazole, 5,6-dimethylbenzothiazole, 4- phenylbenzothiazole, S-phenylbenzothiazole, 6- phenylbenzothiazole, 5-hydroxybenzothiazole, 6- hydroxybenzothiazole, 4-methoxybenzothiazole, 5 -methoxybenzothiazole, 6-methoxybenzothiazole, S-ethoxybenzothiazole, 6-ethoxybenzothiazole, 5,6-dimethoxybenzothiazole, 5,6-methylenedihydroxy-benzothiazole, 5- diethylaminobenzothiazole, 6- diethylaminobenzothiazole, fi-nitro-benzothiazole, S-carboxybenzothiazole, 5-sulfobenzothiazole, 6- cyanobenzothiazole, S-trifluoromethylbenzothiazole, S-benzoylbenzothiazole, tetrahydrobenzothiazole or 7-oxo-tetrahydrobenzothiazole), naphthothiazole (e.g. naphtho[l,2-d]thiazole, naphtho[ 2, l -d]thiazole, 7-methoxy-naphtho[2, l d]thiazole or 8 methoxynaphtho[l,2-d]thiazole), selenazole (e.g. 4-methylselenazole or 4- phenylselenazole), benzoselenazole (e. g., benzoselenazole, 5-chlorobenzoselenazole, 5,6-dimethylbenzoselenazole, 5-hydroxy-benzoselenazole, 5- methoxy-benzoselenazole or tetrahydrobenzoselenazole), naphthoselenazole (e.g. naptho[ 1 ,2-d]selenazole or naphtho[2, l d]selenazole), oxazole (e.g. oxazole, 4- methyloxazole, 4-phenyloxazole or 4,5 diphenyloxazole), benzoxazole (e.g., benzoxazole, 5-chlorobenzoxazole, 6-chlorobenzoxazole, 5,6-dimethylbenzoxazole, S-phenylbenzoxazole, S-hydroxybenzoxazole, S-methoxybenzoxazole, 5- phenylbenzoxazole, S-hydroxybenzoxazole, 5- methoxybenzoxazole, S-ethoxybenzoxazole, 6- dialkylaminobenzoxazole, S-carboxybenzoxazole, 5-sulfobenz0xazole, sulfonamidobenzoxazole or S-carboxyvinylbenzoxazole), naphthoxazole (e.g., naphtho[ l ,2-d1oxazole, naphtho[2, 1 -d]oxazole or naphtho[2,3-d]oxazole), 3,3-dialkylindolenine (e.g., 3,3-dimethylindolenine, 3,3,5-trimethylindolenine or 3,3-dimethyl-5-methoxyindolenine), Z-pyridine (e.g., pyridine, 3-methylpyridine, 4-

3 4 methylpyridine, S-methylpyridine, 6- -methoxyquinoline, 7-methylquinoline or 8- methylpyridine, 3,4-dimethylpyridine, 3,5- methylquinoline), isoquinoline (e.g., isoquinoline di thyl yr idine, 3,6-di thylpyridin 4,5- or 3,4-dihydroisoquinoline), thiazoline (e.g., thiazdi th l y idi 4,6-di th l idi 4- oline or 4-methylthiazole), oxazolone and heterochl y idi 5- h1 idi 6 cyclic groups of the pyrroline, tetrahydropyridine, chloropyridine, 3-hydroxypyridine, 4- thladiazole, oxadiazole, pyrimidine, triazine or h d idi 5-h d idi 3- benzothiazine and pyrimidone or thiopyrimidone. phenylpyridi 4- h idi or 6- The aryl groups and heterocyclic groups may carry phenyl yridi 4 idi 2 h 1 idi any other additional substituents, e.g., alkyl groups 3- h l idi 2,3-di h idi 2 5. which preferably contain up to three carbon atoms dimethyl yrjdin 2,6-di th l idi 2- such as methyl or ethyl, halogen such as chlorine chloropyridine, 3-chloro y idi 2- or bromine, hydroxyl, alkoxy preferably with up to hydroxypyridine or 3-h dr py idi 2- three carbon atoms such as methoxy or ethoxy, hyquinoline (e g quinoline, 3- thylq i li 5- droxyalkyl, alkylthio, aryl such as phenyl, aralkyl methylquinoline, 7-methylquinoline, 8- such as benzyl, amino, substituted amino or nitro. methylquinoline, 6-chloroquinoline, 8- The following are examples of suitable compounds. chloroquinoline, o-methoxyquinoline, 6- The absorption maxima are measured in methanolic ethoxyquinoline, 6-hydroxyquinoline, 8- solution unless otherwise indicated. In the table, hydroxyquinoline or 5-ox0-5,6,7,8- ACOH means glacial acetic acid and DMSO dimethyltetrahydroquinoline), 4-quinoline (e.g., quinoline, sulfoxid.

Compound Absorption Sensitization maximum maximum b s a CH-CH=CH- N: 458 555 H c H cH v 2 o- N =CH-CH=CH N@O 490 585 i on Absorption Sensitization Compound maximum maximum 470 (AGOH) 466 (Aceton) e v 010 11 mam-CH 495 (Aceton) I on 483 (Ac eton) Absorption Sensitization maximum maximum Compound O 5 7 5 w u 4 4 H C O 3 9 3 H 3 J H C H C N C N w 0 m H H C H C H 4 H H C H5 0% 6 N 3 4 4 1 0 5 8 6 4 9 J 5 5 H 9 m e N 2 4 S/\\ C o 2 H C. 4 H H C C I 0 lo 7 O 5. 1

01 i 1 9 v B 'Q B 13 14 Compound Absorption Sensitization maximum maximum V H 0 CH3 v 481 570 21 N -CH-CH=CH iq (ACOH) Cl O/Lli? 464 545 22 CH- CH=CH rg (DMSO) Q 470 560 23 o- N CH-CH=CH O 470 5 5 24 CH CH=CH- (Aceton) Compound 1 I? Absorption Sensitization maximum maximum H,- 25 ogcH-c11=cH- g 425 495 Q Q I Q H2 '1 26 cH-cH=cH- :i 419 =3 4 7 v 27 0 N cH--cH cH-Q 3 520 434 20 2a cH omen-SID v I 5 17 I 1 Compound Absorption Sensitization maximum maximum 1? W 29 N CH-CH=CH(N 457 555 e H3C--SO3 H36 CH3 00H 3o 0 N CH-CH=CH. Q 485 580 31 Oi E=CH-CH=CH 448 540 l Q (Aceton) 11 9 H (Aceton) I Q C I l9 Compound Absorption Sensitization maximum maximum OCH 486 580 33 O N CH-CH=CH F tion.

Silver halide emulsionssensitized with the present dyes'are not or only slightly colored so that they can also be used coated on paper supports. The emulsions may be fogged by the usual methods, for example by the action of light or so-called chemical fogging agents, for example stannous chloride, formaldehyde, thiourea dioxide. Another advantageous method of fogging the emulsions consists in adding a reducing compound, for example thiourea dioxide, and the compound of a metal which is more electropositive than silver, forexample a gold salt, e.g. potassium chloroaurate, as described in British Pat. Specification No. 723,019.

. Typical reducing compounds which are suitable for preparing such fogged silver halide emulsions are, for example, stannous salts, such as stannous chloride, hydrazine, sulfur compounds such as thiourea dioxide, phosphonium salts, e.g., tetra(hydroxymethyl)- phosphonium chloride. Typical compounds of metals which are more electropositive than silver are, for example, compounds of gold, rhodium, platinum, palla-.

dium and iridium. It is preferred to use soluble salts of the said 'noble metals, e.g., potassium chloroaurate, auric chloride and (NH -PdCl The concentration of the reducing agents or the compounds of the metal which is more electropositive than silver used for fogging can vary within wide limits. in general, concentrations of 0.0005 to about 0.06 milli-' equivalents of reducing agent and about 0.001 to about ().()I milli-mols of the noble metal salt per mol silver halide have proved sufficient.

Fogging can be also accomplished with the method of silver halide digestion described by WOOD in J.phot.Science l (1963) page 163, at pAg values between 2 and 5 and pH values of about 6.5.

Any type of direct positive photographic emulsions can be spectrally sensitized by the sensitizing dyes of the present invention. Suitable direct positive emulsions include silver halide emulsions the grains of which have high internal sensitivity in particular silver halide emulsions containing internal electron traps. Particular utility is exhibited by direct positive silver halide grains comprising a central core of a silver halide which contains centres which act aselectron traps and an outer shell covering said core comprising a fogged silver halide that develops to silver without exposure. Emulsions of that type are disclosed by E. MOlSAR and F. WAG- NER in Berichte der Bunsengesellschaft fur physikalische Chemie 67 (1963), pages 356 e 359. We furthermore refer to British Pat. specifications Nos. l,O27,l46 and 1,151,781 or to French Pat. specification No. 1,585,791. The formations of the centres or specks in the inside of the grains particularly on the core of the composite grain are produced as known per se by chemical sensitizing the emulsion with compounds of noble metals in particular gold or iridium salts are sulfur compounds such as thiosulfates. In particular useful is a treatment with noble metal salts and sulfur compounds.

. The spectral sensitizers of the present invention can also be applied to direct positive emulsions which are fogged on the surface so that they can be developed to silver without exposure and which contain at the surface electron acceptors such as desensitizing dyes. Suitable dyes for this purpose are wellknown. Reference is made, e.g., to pinacryptol yellow or nitrosubstituted polymethine dyes-The technic of desensitizationand the chemical structure of suitable desensitizing dyes are described e.g., by O. RlESTER in Mitteilungen aus den Forschungslaboratorien der Agfa," Volume 1 (1955), page 44 or in the handbook Grundlagen der photographischen Prozesse mit Silberhalogeniden", Volume 3, page 1077. The direct positive sensitizing dyes of the present invention can be used in combination with further sensitizing dyes capable of sensitizing direct positive emulsions and desensitizing negative silver halide emulsions as described, for example, in US.

Pat. specifications Nos. 3,314,796 or 3,505,070.

Further suitable direct positive emulsion are described in German Pat. specifications Nos. 606,392 or 21 642,222 or in UK Pat. specifications Nos. 581,773 or 655,009.

The direct positive emulsions may also contain mercury salts and thallium salts as described in British Pat. specification No. 1,203,744 or US. Pat. specification No. 3,620,750.

The silver halide of the silver halide emulsions to which the new cyanine dyes may be added may consist of one of the usual silver halides used for preparing photographic silver halide emulsions, i.e., for example silver bromide, silver iodide, silver chloride, silver chlo robromide, silver bromoiodide and silver chlorobrornoiodide.

The new dyes may be incorporated with silver halide emulsions at the usual concentrations, for example concentrations of about 50 to 2.000 mg, preferably about 400 to 800 mg/mol of silver halide.

The new cyaninedye's are preferably added to the washed silver halide emulsions and dispersed in them as uniformly as possible. The incorporation of the dyes in the emulsions may be carried out by the usual known methods, for example, the dyes may be added to the emulsions from solutions in suitable solvents. The solvents must, of course, be selected so that they have no adverse effect on the light-sensitive photographic material which is to be produced. Suitable solvents are, for

example, methanol, isopropanol, acetone and water,

either separately or mixed with each other.

The binder of the silver halide emulsions to which the cyanine dyes accordingto the invention may be added may be any of the hydrophilic colloids commonly used.

The emulsions containing one or more cyanine dyes according to the invention may be applied to the usual opaque or transparent photographic supportsused for the preparation of photographic materials, for example supports of glass, cellulose acetate, cellulose acetobutyrates or polyesters, e.g., polyethylene terephthalate, or supports of baryta-coated paper or paper coated with polyolefines such as polyethylene.

The photographic silver halide emulsions to which the new cyanine dyes are added, as well as the other layers of a photographic material which is prepared using these emulsions may be hardened by the addition of the usual hardeners such as aldehyde hardeners, e. g., formaldehyde or mucochloric acid.

The good sensitizing effect is preserved even in the presence of water-soluble and emulsified color couplers. The emulsion may also contain the usual wetting agents, stabilizers, brightening agents and other additives.

EXAMPLE 45 mg of sensitizer 3 in the form of a 1:1000 solution in methanol are added with stirring to 1 kg of a direct positive emulsion which has been prepared by chemical based on the amount of silver, and the mixture is left.

to digest for 10 minutes. 10 ml of a 4 percent aqueous solution of saponin as wetting agent and 25 ml of a 5 the art and developed for 5 minutes at 20C using a developer of the following composition:

p-methylaminophenol 3.5 g anhydrous sodium sulfite 60.0 g hydroquinone 9.0 g anhydrous sodium carbonate 40.0g potassium bromide 3.5 g

made up to l litre with water.

The layer is then fixed with an aqueous solution of sodium thiosulfate in the usual manner.

A positive image of the test wedge with exceptional whites and an excellent gamma value (gradation) is obtained. The spectral sensitization curve is represented in FIG. 2.

FIG. 1 shows for comparison the sensitivity curve obtained without sensitizer.

When sensitizer 3 is replaced by an equal quantity of compound 8, the sensitization curve of FIG. 3 is obtained, and when an equal quantity of compound 9 is used, the sensitization curve of FIG. 4 is obtained. The sensitization curve of FIG. 5 is obtained when using compound 17 in the same way.

We claim:

l. Light-sensitive photographic direct positive material containing at least one fogged silver halide emulsion layer which layer contains an isoindolinone polymethine sensitizer of the following formula:

in which R represents an aliphatic group having up to 6 carbon atoms or a phenyl group;

R stands for hydrogen or halogen;

R represents an aliphatic group having up .to 6 carbon atoms, cycloalkyl or aryl;

n is 0 or 1;

X represents any anion;

Q stands for the ring members required for completing a 5- or 6-membered heterocyclic ring based on thiazole, benzothiazole, naphthothiazole, selenazole, benzoselenazole, naphthoselenazole, oxazole, benzoxazole, naphthoxazole, 3,3- dialkylindolenine, Z-pyridine, 4pyridine, 2- quinoline, 4-quinoline, isoquinoline, thiazoline, oxazoline, pyrroline, tetrahydropyridine, thiadiazole, oxadiazole, pyrimidine, triazine, benzothiazine, pyrimidone or thiopyrimidone, which heterocyclic ring may contain a fused benzene or naphthalene rmg' 

